Ornamental Grass Pruning – A Winter Task

The term “ornamental grass” is a catch-all phrase used to describe grasses and “grass-like” plants.  Individual species are adapted to a wide variety of landscape sites (i.e., wet or dry, sun or shade, hot or cold climates, and varied salt tolerance). Growth habits range from low ground covers to intermediate shrub-like plants to very tall hedge-like plants. Ornamental grasses are very dynamic; the size, shape, texture, and color of grass changes with every season.

Grasses with foliage that dies in the winter and remains dormant until the weather warms in the spring are considered deciduous.  The winter character of deciduous ornamental grasses adds tremendous interest to the winter garden when contrasted with evergreen plants or structures such as walls or fences.  The dried foliage of deciduous grasses creates sound as it expands and contracts in response to changes in temperature or moisture, while interaction with wind creates movement in the garden. For these reasons, pruning of the dead foliage and inflorescences is not recommended at the time of the first frost.

Pruning of ornamental grasses should be done in late winter or early spring, just prior to new shoot growth.  In Northwest Florida, gardeners should target the end of February to prune ornamental grasses.  For deciduous grasses, such as Japanese silver grass (Miscanthus sinensis), the old foliage may be completely removed within inches of the soil. Be cautious to not remove the growth point by leaving the grass clump at least 4 inches high.  For evergreen grasses, such as muhly grass (Muhlenbergia capillaris), the ragged leaves can be removed to neaten the appearance of the plant without shortening all the way to the ground. So, depending on the damaged portions, the remaining grass clump can be 6-18 inches high after pruning.  Grasses recover quickly from a heavier pruning.  Within a few months the plant will have completely regrown.  If desired, old flower stalks and seed heads may be removed any time they no longer have a neat appearance.  For more information on ornamental grass species and growing tips, please visit the EDIS Publication: Considerations for Selection and Use of Ornamental Grasses.